Flow tube for use in subsurface valves

ABSTRACT

According to one or more aspects of the present disclosure, an engaging member for operating a subsurface valve between an open position and a closed position includes a bottom portion comprising a terminal end adapted for contacting a valve closure member, the bottom portion having a first material characteristic and an upper portion having a second material characteristic that is quantitatively different from the first material characteristic. The material characteristics include, without limitation, strength, coefficient of friction, and the modulus of elasticity.

BACKGROUND

This section provides background information to facilitate a betterunderstanding of the various aspects of the present invention. It shouldbe understood that the statements in this section of this document areto be read in this light, and not as admissions of prior art.

The present disclosure relates generally to wellbore operations andequipment and more specifically to subsurface valves and engagingmembers (e.g., flow tubes, sleeves) that can be utilized to open and/orclose the valve.

Equipment is utilized in wells (e.g., wellbore, bore hole) to facilitatethe flow of fluids in the well relative to the subterranean formationsurrounding the well. Valves are utilized in the well (e.g., subsurface)to inhibit or otherwise control the fluid flow through the wellequipment. For example, subsurface safety valves are often disposed inthe well to prevent or limit the flow of fluids in an undesireddirection. For example, flapper valves are often utilized to enable flowof fluid in a first direction while blocking fluid flow in the oppositesecond direction.

For example, many subsurface safety valves utilize a flapper as aclosure mechanism fitted within a body or housing to enable control overfluid flow through a primary longitudinal bore upon an appropriateapplied signal (e.g., pressure, flow, electrical or other means) from acontrol system. The applied signal is commonly a rapid reduction of thehydraulic operating pressure that holds the valve open, therebyfacilitating shut-in of the production or injection fluid flow byclosure of the valve. The closure mechanism typically is movable betweenthe open and closed position by movement of a tubular device, oftencalled a flow tube. The flow tube can be moved to the open position oroperated by the valve actuator which is motivated by hydraulics,pressure, electronic, or other applied signals and power sources. Theshifting of the flow tube to a closed position can be performed forexample by a mechanical power spring and/or a pressurized accumulatorthat applies a required load to move the flow tube to the closedposition upon interruption of the “opening” signal. As a result, thevalve can be required to close against a moving flow stream. Fluidforces acting on the closure member can result in damage to the flowtube and thus to the valve. Further, impacts from the closure memberagainst the end of the flow tube can deform or gall the flow tubeleading to failure to operate the valve when needed.

SUMMARY

According to one or more aspects of the present disclosure, an engagingmember for operating a subsurface valve between an open position and aclosed position includes a bottom portion comprising a terminal endadapted for contacting a valve closure member, the bottom portion havinga first material characteristic; and an upper portion having a secondmaterial characteristic that is quantitatively different from the firstmaterial characteristic. In some embodiments the material characteristicincludes strength and the first material characteristic is greater thanthe second material characteristic.

According to one or more aspects of the present disclosure a subsurfacevalve configured to move between an open position and a closed positionin response to an applied signal includes a housing having a bore; aclosure member disposed with the housing; a flow tube movably disposedin the housing, the flow tube comprising a terminal end positioned tocontact the closure member, wherein the closure member is actuated tothe open position in response to a certain force applied to the flowtube and actuated to the closed position upon relief of the certainapplied force; and a bottom portion of the flow tube proximate theterminal end comprising a first material characteristic that is and thesecond characteristic differ different than a second materialcharacteristic of an upper portion of the flow tube.

A method, according to one or more aspects of the present disclosure,for operating a subsurface valve includes disposing a valve in awellbore, the valve including a housing having a bore, a closure memberdisposed with the housing, a flow tube movably disposed in the housing,the flow tube comprising a terminal end positioned to contact theclosure member and a bottom portion of the flow tube proximate theterminal end having a first material characteristic that isquantitatively different than a second strength characteristic of anupper portion of the flow tube; moving the closure member to an openposition in response to a certain force being applied to the flow tube;and moving the closure member to an open position in response toreleasing at least a portion of the certain force applied to the flowtube.

The foregoing has outlined some of the features and technical advantagesof the present invention in order that the detailed description of theinvention that follows may be better understood. Additional features andadvantages of the invention will be described hereinafter which form thesubject of the claims of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic view of an embodiment of a wellbore completionincorporation a valve and flow tube according to one or more aspects ofthe present disclosure.

FIG. 2 is a partial cross-sectional view of an embodiment of asubsurface valve 12 and flow tube 36 according to one or more aspects ofthe present disclosure illustrated in the open position.

FIG. 3A is a partial cross-sectional view of another embodiment of asubsurface valve, depicted in the open position, utilizing a flow tubeaccording to one or more aspects of the present disclosure.

FIG. 3B is a partial cross-sectional view of the subsurface valve ofFIG. 3A depicted in the closed position.

FIG. 4 is a cross-sectional view of a section of a flow tube accordingto one or more aspects of the present disclosure.

FIG. 5 is a cross-sectional view of a section of another embodiment of aflow tube according to one or more aspects of the present disclosure.

FIG. 6 is a cross-sectional view of a section of another embodiment of aflow tube according to one or more aspects of the present disclosure.

FIG. 7 is a cross-sectional view of a section of another embodiment of aflow tube according to one or more aspects of the present disclosure.

FIG. 8 is a cross-sectional view of a section of another embodiment of aflow tube according to one or more aspects of the present disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.Moreover, the formation of a first feature over or on a second featurein the description that follows may include embodiments in which thefirst and second features are formed in direct contact, and may alsoinclude embodiments in which additional features may be formedinterposing the first and second features, such that the first andsecond features may not be in direct contact.

As used herein, the terms “up” and “down”; “upper” and “lower”; “top”and “bottom”; and other like terms indicating relative positions to agiven point or element are utilized to more clearly describe someelements. Commonly, these terms relate to a reference point as thesurface from which drilling operations are initiated as being the toppoint and the total depth of the well being the lowest point, whereinthe well (e.g., wellbore, borehole) is vertical, horizontal or slantedrelative to the surface. The terms “pipe,” “tubular,” “tubular member,”“casing,” “liner,” “tubing,” “drill pipe,” “drill string” and other liketerms can be used interchangeably. The terms may be used in combinationwith “joint” to mean a single unitary length; a “stand” to mean one ormore, and typically two or three, interconnected joints; or a “string”meaning two or more interconnected joints.

In this disclosure, “hydraulically coupled” or “hydraulically connected”and similar terms (e.g., fluidic, pneumatic), may be used to describebodies that are connected in such a way that fluid pressure may betransmitted between and among the connected items. The term “in fluidcommunication” is used to describe bodies that are connected in such away that fluid can flow between and among the connected items. It isnoted that hydraulically coupled may include certain arrangements wherefluid may not flow between the items, but the fluid pressure maynonetheless be transmitted. Thus, fluid communication is a subset ofhydraulically coupled.

It is common to use subsurface valves in wells to control fluid flowthrough the wellbore. The subsurface valves are commonly actuated to afirst position (e.g., open) by the application of hydraulic pressure,for example from the surface, and biased to the second position (e.g.,closed) by a biasing mechanism (e.g., stored energy assembly), such asan enclosed pressurized fluid chamber or a mechanical spring. Thefluidic pressure may be applied to a piston and cylinder assembly, forexample, that acts against the biasing force of the biasing mechanism toopen and hold the safety valve opened. The biasing force acts on thepiston to move a flow tube to a position allowing the closure member ofthe valve close to move to the closed position when the fluid pressureis reduced below a certain value. Examples of some subsurface safetyvalves are disclosed in U.S. Pat. Nos. 4,161,219 and 4,660,646 and U.S.Patent Application Publications 2009/0266555, 2010/0006295 and2010/0139923, which are all incorporated herein by reference.

FIG. 1 is a schematic of a well 10 incorporating an embodiment of asubsurface safety valve 12 comprising a flow tube according to one ormore aspects of the present disclosure. Depicted well 10 includes awellbore 16 extending from a surface 18 and lined with casing 20. Atubular string 22 is disposed in wellbore 16. A valve 12, described as asubsurface safety valve for purposes of description, is connected withintubular string 22. In this example, subsurface safety valve 12 isoperated by a fluidic pressure, for example hydraulic pressure.Hydraulic system 24 can provide hydraulic pressure to subsurface safetyvalve 12 through a manifold 26 and control line 28.

Hydraulic pressure is provided through control line 28 to subsurfacesafety valve 12 actuating valve closure member 30 to the open positionallowing fluid to flow across subsurface safety valve 12 within tubularstring 22. Hydraulic pressure is maintained above a certain level tohold valve closure member 30 in the open position. To actuate subsurfacesafety valve 12 to the closed position, as shown in FIG. 1, thehydraulic pressure via control line 28 is reduced below a certain level.As is known in the art, the hydraulic pressure is reduced below thelevel of the force that biases valve closure member 30 to the closedposition.

FIG. 2 is a partial cross-section view of an embodiment of a subsurfacevalve 12 and flow tube 36 according to one or more aspects of thepresent disclosure illustrated in the open position. Depicted valve 12is a subsurface safety valve comprising a housing 32 having alongitudinal bore 34. Valve closure member 30 is a flapper in thisembodiment. An engaging member 36 (e.g., flow tube, sleeve, tubularmember) having a central longitudinal bore co-axially aligned with bore34 of housing 32 is movably disposed within housing 32. An engagingmember 36 is generally referred to as a flow tube. In this embodiment,the valve actuation assembly comprises a piston 38 disposed with flowtube 36. Piston 38 is positioned within cylinder 14 and is in fluidicconnection with fluidic chamber 42. Biasing mechanism 40 biases flowtube 36 upward in the embodiment depicted in FIGS. 1 and 2 toward theclosed position. Biasing mechanism 40 is illustrated as a spring but mayinclude alternatively or in combination other biasing mechanism such asand without limitation a pressurized fluid.

To open subsurface safety valve 12, as illustrated in FIG. 2, fluidpressure is applied through control line 28 to piston 38 positioned incylinder 14 providing a downward force on flow tube 36 that is greaterthan the counteracting force applied to flow tube 36 by biasingmechanism 40. The terminal end 44, referred to herein as contact end, offlow tube 36 physically contacts closure member 30, or a lever or otherclosure member device, moving flapper 30 about pivot connection 46 tothe open position permitting fluid flow through bore 34 opened throughvalve 12 and flow tube 36 toward the surface. Subsurface valve 12 ismaintained in the open position by the maintenance of hydraulic pressureagainst piston 38.

To close subsurface safety valve 12, for example due to a pressure kickin the well, the hydraulic pressure can be relieved from control line 28to a level such that biasing mechanism 40 moves flow tube 36 permittingvalve closure member 30 to close. It is often desired for valve 12 torespond quickly to a close signal. As a result, closure member 30 canslam against flow tube 36, in particular contact end 44.

As further described below, flow tube 36 comprises a bottom portion 48that includes contact end 44 and that has a material characteristic thatquantitatively differs from the same material characteristic of upperportion 50 of flow tube 36. The material characteristics may include,without limitation, one or more of strength, elasticity (e.g., modulusof elasticity), flexibility, coefficient of friction (e.g., resistanceto fluid flow), anti-galling, and the like. For example, the bottomportion 48 can be constructed to be more resistant to deformation and/orgalling relative to upper portion 50. Bottom portion 48 may have a firstmaterial characteristics that has a lower coefficient of friction andreduces the resistance to the flow of fluid and debris relative to topportion 50. In some embodiments, bottom portion 48 may be more flexibleand/or have a greater yield strength than upper portion 50. In someembodiments bottom portion 48 can have a strength greater than the upperportion 50 and in other embodiment bottom portion 48 can have a strengthless than or the same as upper portion 50.

In some embodiments, bottom portion 48 is a separate piece of materialconnected with the upper portion 50 for example by welding, bonding andthreading. In other embodiments, bottom portion 48 may be continuousportion of flow tuber 36 with upper portion 50. The material ofconstruction of bottom portion 48 may be the same or different than thatmaterial of construction of upper portion 50. The different materialcharacteristic of bottom portion 48 from upper portion 50 may beachieved by the material of construction, the manner of construction,and/or inclusion a material characteristic changing element (e.g.,substance). For example, a layer of material may be disposed with on asurface of bottom portion 48. The characteristic changing element ormaterial may be disposed with bottom portion 48, by coating, deposition,or attachment (e.g., bonding, welding, etc.) as a layer of material. Forexample, bottom portion 48 can be a section of flow tube 36 thatcomprises a layer of material or the like that has a materialcharacteristic such as higher strength than that of the upper portion50. For example, bottom portion 48 may comprise a layer or strip ofmaterial on the inner surface 52 and/or exterior surface 54 (FIGS. 3Band 4) that creates provides a different material characteristic betweenbottom portion 48 and upper portion 50. For example, a material disposed(e.g., by deposition) on the exterior surface 54 of bottom portion 48can limit galling and abrasion and/or reduce friction along the interiorwall 56 of housing 32 (FIG. 3B).

FIG. 3A is a partial cross-sectional view of another embodiment of asubsurface valve 12, depicted in the open position, utilizing a flowtube 36 according to one or more aspects of the present disclosure. Inthis embodiment, contact end 44 of flow tube 36 comprises is profiled,for example as disclosed in U.S. Patent Appl. Publ. 2010/0139923 whichis incorporated herein by reference. In the open position, fluid isflowing through the longitudinal bore 34 of valve 12 toward the surface.

FIG. 3B is a partial cross-sectional view of subsurface valve 12 of FIG.3A, depicted in the closed position, utilizing a flow tube 36 accordingto one or more aspects of the present disclosure.

FIG. 4 is a cross-sectional view of section a flow tube 36 according toone or more aspects of the present disclosure. Flow tube 36 comprisesbottom portion 48 terminating at contact end 44 and an upper portion 50.Upper portion 50 and bottom portion 48 have different materialcharacteristics (e.g., yield strength, elastic flex, reduced friction).For example, bottom portion 48 is harder and/or has a higher yieldstrength than upper portion 50 in the depicted embodiment, to withstandthe higher flow induced flow forces and/or impact forces associated withclosure of the valve. Upper portion 50 may be constructed of lessexpensive material, for example carbon steel, than the bottom portion48. Examples of materials of construction of bottom portion 48 include,without limitation, nickel based alloys, cobalt-based alloys, andcomposite materials.

In the depicted embodiment, bottom portion 48 is a unitary piece that isconnected to upper portion 50 via a connection 58. Connection 58 may beby any manner suitable for connecting the opposing pieces, for examplethreading, bonding and welding. Connection 58 is depicted in FIG. 4 aswelding or bonding. Connection 58 is depicted in FIG. 5 as a threadedconnection.

FIG. 6 is a cross-sectional view of another embodiment of a flow tube 36according to one or more aspects of the present disclosure. In thisembodiment, bottom portion 48 is constructed of a two or more layers ofmaterial, the layers indentified as 48 a, 48 b, 48 c, etc. The layersmay be constructed of the same material or of different materials. Forexample, layers 48 a, 48 b, 48 c are constructed of the same material inthe depicted embodiment. For example, layers 48 a, 48 b and 48 c areflat metal plates (e.g., steel) that are welded together and formed intothe tubular (e.g., cylindrical) bottom portion 48. Bottom portion 48 isthen connected to upper portion 50 via connection 58. Connection 58 isdepicted as a weld in this embodiment by way of an example. The mannerof construction of bottom portion 48, for example by layering material,can provide a the desired material characteristic. For example,utilizing a layered construction can provide increased strength,flexibility, and/or elasticity.

FIGS. 7 and 8 are cross-sectional views of a portion of a flow tube 36according to one or more aspects of the present disclosure. In FIG. 7 amaterial characteristic element (e.g., material, substance) 60 which isreferred to as a strip for purposes of description herein is disposed atthe inner surface 52 of flow tube 36. Strip 60 is depicted disposedalong the outer surface 54 of flow tube 36 in FIG. 8. Strip 60 comprisesa material having a desired material characteristic and/or whichprovides a desired material characteristics when disposed with bottomportion 48. Strip 60 may be a material that has a high strength suchthat a surface layer of high strength is formed on bottom portion 48.For example, strip 60 may comprise, without limitation, a nickel-basedalloy or a cobalt-based alloy. Strip 60 may comprise one or morematerials to achieve the desired material characteristics. For example,strip 60 may be formed of layers of material such as described generallywith reference to FIG. 6. As described above, material 60 may provideand/or achieve a material characteristic other than strength, forexample strip 60 may be a material that reduces the friction of asurface of bottom portion 48. Strip 60 may be disposed on bottom portion48 by coating, deposition, or welding for example.

Bottom portion 48 and upper portion 50 are depicted in FIG. 7 as asections of a unitary tubular flow tube 36 in which strengthened strip60 is set along the inner surface 52. In FIG. 8, bottom portion 48 isdepicted as an individual member that is connected to upper portion 50via connection 58.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions andalterations herein without departing from the spirit and scope of thepresent disclosure. The scope of the invention should be determined onlyby the language of the claims that follow. The term “comprising” withinthe claims is intended to mean “including at least” such that therecited listing of elements in a claim are an open group. The terms “a,”“an” and other singular terms are intended to include the plural formsthereof unless specifically excluded.

1. An engaging member for operating a subsurface valve between an openposition and a closed position, the engaging member comprising: a bottomportion comprising a terminal end adapted for contacting a valve closuremember, the bottom portion having a first material characteristic; andan upper portion having a second material characteristic that isquantitatively different from the first material characteristic.
 2. Theengaging member of claim 1, wherein the bottom portion is formed of amaterial different than the material forming the upper portion.
 3. Theengaging member of claim 1, wherein the bottom portion comprises amaterial disposed along a surface of the bottom portion.
 4. The engagingmember of claim 3, wherein the material disposed along the surface ofthe bottom portion by one selected from the group of welding, coating,and deposition.
 5. The engaging member of claim 1, wherein the bottomportion comprises two or more layers of material.
 6. The engaging memberof claim 1, wherein the bottom portion is a separate member connected tothe upper portion by a connection.
 7. The engaging member of claim 1,wherein the material characteristic comprises strength, and the firstmaterial characteristic is greater than the second materialcharacteristic.
 8. A subsurface valve configured to move between an openposition and a closed position in response to an applied signal, thevalve comprising: a housing having a bore; a closure member disposedwith the housing; a flow tube movably disposed in the housing, the flowtube comprising a terminal end positioned to contact the closure member,wherein the closure member is actuated to the open position in responseto a certain force applied to the flow tube and actuated to the closedposition upon relief of the certain applied force; and a bottom portionof the flow tube proximate the terminal end comprising a first materialcharacteristic that is quantitatively different than a second materialcharacteristic of an upper portion of the flow tube.
 9. The subsurfacevalve of claim 8, wherein the bottom portion and the upper portion areconstructed of different materials of construction.
 10. The subsurfacevalve of claim 8, wherein the bottom portion comprises a materialdisposed along a surface of the bottom portion, wherein the disposedmaterial provides the first material characteristic.
 11. The subsurfacevalve of claim 10, wherein the material characteristic comprises oneselected from the group of strength, coefficient of friction, andmodulus of elasticity.
 12. The subsurface valve of claim 11, wherein thematerial characteristic comprises strength, and the first materialcharacteristic is greater than the second material characteristic. 13.The subsurface valve of claim 8, wherein the bottom portion comprisestwo or more layers of material.
 14. The subsurface valve of claim 13,wherein at least two of the two or more layers are constructed of thesame material.
 15. The subsurface valve of claim 8, wherein the bottomportion is a separate member connected to the upper portion by aconnection.
 16. The subsurface valve of claim 8, wherein the bottomportion is constructed of a plurality of layers of plate material weldedtogether and formed into a tubular shape.
 17. A method for operating asubsurface valve; the method comprising: disposing a valve in awellbore, the valve comprising: a housing having a bore; a closuremember disposed with the housing; a flow tube movably disposed in thehousing, the flow tube comprising a terminal end positioned to contactthe closure member; and a bottom portion of the flow tube proximate theterminal end comprising a first material characteristic that isquantitatively different from a second material characteristic of anupper portion of the flow tube; moving the closure member to an openposition in response to a certain force being applied to the flow tube;and moving the closure member to an open position in response toreleasing at least a portion of the certain force applied to the flowtube.
 18. The method of claim 17, wherein the material characteristiccomprises one selected from the group of strength, coefficient offriction, and modulus of elasticity.
 19. The method of claim 18, whereinthe material characteristic comprises strength, and the first materialcharacteristic is greater than the second material characteristic. 20.The method of claim 17, wherein the bottom portion is constructed of aplurality of layers of plate material welded together and formed into atubular shape.